Impression material



Patented Nov. 3, 1953 IM'PRESSION MATERIAL EdWinHMLochridge, Glendale; -.Ca;lif;,'.assignor to;- a Dental #Perfction Company, Glendale, Calif, v a corporation 'ofCaIifornia N oDrawingz Application December 1951, Serial N 0. 260,929

Claims; (Cl. 18-47)' This inventionl relatesto a" new-impression composition. a More specificallyit: relatesyto acomposition for making: dentaltimpressionsr V For many dental purposes,- such asthelmaking. of fullv dentures; partial dentures, bridges; etc., it is necessary for the dentist to be able toaccus ratelyreproduceportions-of the mouth.- These reproductions are made bythe :use of impression compounds;

Myimpressionmaterial containsa suitable. gel forming iagent such: as sodium potassium or; am.- monium a1ginate,=sodium or 'potassiumcarbonymethyl cellulose or sodiumpotassiumflor ammo nium pectate- Mixtures. of the-eforegoing gel formingagents-may-also be used in mynewscomr. position.

To the above add lead compound, such as lead-oxide; basic lead' sulfate or; lead-silicate. Lead-silicate in the form oi-lead monosilicateor lead disilicate is especially suitable Asssubstitutes for" these =-lead eompoundsI.may also-use calcium: compounds in the form :of calcium. sulfate, calcium oxide; or calcium hydroxidezlslaked lime).

To the above I adda'fluosilicate. Most fiuosilicates appear to "give-satisfactory results; :however I prefer: tO' uSeilI sodium -fluosi1icate,=1 potassium fluosilicate, alumimimtfiuosilicate or ammonium fluosilicate.

To the foregoing-.1 also..add a filler such as diatomaceous earth in a finely ground form. Other fillers; such as full'er s 1 earth or talc may also be used.

To the above I also-addra comp0und.-to:con. trol the-setting characteristicsof the composis tion. For this purpose; have .foundlthe sodium salt of ethylene. diamine tetra-- aceticlacid to be yeryeefiectiye. The other. alkalimetalas'alts may also be employed: For example,-;the potassium or lithium salt of ethylene diamine tetra aceticacid' also' gives satisfactory results; To the above I'add sufiicient-water to form a stiff 'paste when spatul'ate'd (mixed) and' then place this cast into a' dental trayfor taking the impression-y Inthiscomposition the metal compounds react with the-pectates, alginates'and alkali metalsalts of carboxymethyl cellulose to form a water insoluble gel.

It is therefore an object of the present invention to produce a composition 1 of matter suitable and useful asa dental impression material b'y blending'a-metalcompound; a fill'er, a fluosili cate, a gel iorming" agent, an agent to control set ting such" as the-alkali *metalsaltof ethylene diami-ne-tetra acetic acid and waten I have found that the alkali 'metalsalts of ethylenediaminectetra .acetic acidifunction effectively to controlthelsetting.characteristics oflmy new composition. If the alkali metal salt of the ethylene dia'mine tetra acetic acid; which has the character of a retarder-and may be referred to as the retarder salt, is omitted from the composition the rate of reaction between'the gel forming agent;ssuchi as sforfrexample, gsodium- Ealginate, and the metal;=isuch=?as;leaid; issso :rapictthat-the impression composition sets up to a stifi gel before it can be introduced into the patients mouth. Therefore; to' retard this gelation or set the alkalizmetalrsalt is added to oherimpression composition. v As progressively larger amounts of the alkali metal "salt of ethylene" diamine'tetra acetic acid are'addewto my dental im'pression composition;thensetting time isrextended. For practical purposes sufiicientofthe alkali metal salt of ethylene diamine tetra acetic acid is added to my composition to maintain the setting time betweemll/z andnld minutes and preferablyfrom 2ato 5.min-utes:at 709 F.

Although s having in (common with retarder's, e. g; phosphates-land carbonates, previously-used in dental. impressiomcompositions, -the,general property of retardinglxwithin the; practical, requirements; of -impression-taking,the rate ofareaction betweemthw-gel forming .agent;;e. s. :an alginate and: the'fimetal salt reactivev therewith to;form 7a; watervinsoluble:elasticwgel,' the present retaizder salt; is: distinguished 1 from such other retarders: not onlywinl its chemical nature,-., but alsoiainzzits :stabilizing; relation to the other .components of the materiahbeforemixingrwithzwater'; andzthereaften it' appears,- in .theparticular manner in which-zit performs-fits:retardeniunce tion; As: toastabilizing: properties,:. it is .known that: in, the presence of moisture: or: excessive humidity; therusual .dry-impressionsmaterials. of-

the t present; typeubut containing: retardersesuch as .the phosphates; and carbonates, have thein eifectiyeness;and-;shelf life impaired; by reason of' prematurenconsumption of some of the 1 re.-' tard'er by chemical :reaction; with 1 the gel; forming, andinsolubilizine; salt; e. g; :calciumv sulfateaor leadi-silicate. Thusrsuchzusual;retardersvappear to :ionize and becomes prematurely: reactive: in the" presence of relatively small amountsof-moisv-e ture.

The present retardertisalt istcharacteristicallm different With?1respect::.to"its-properties in the dry material; in that neither: it; nor the: initial: composition-of theamaterialiare afieotedibyzsuch increased moisture as would corresponduforizexrample, to high atmospheric humidity. Consequently, the chemical condition and shelf life of the material remain stabilized. The reason why the present retarder behaves in this manner, apparently is that it does not consequently ionize or react with the other constituents of the mixture, even at high humidities, and performs its sequestering and retarder function only in the presence of the relatively great amount of water added when the material is used. It is believed that the sequestering action of the present re tarder is essentially a physical effect of the salt, and which is manifested only in the wet mixture. Ethylene diamine tetra acetic acid has the following structure:

N-CHz-CH2N ricoocfig This compound is a substituted carboxy acid of ethylene diamine.

The di-sodium salt of ethylene diamine tetra acetic acid has the following structure:

CHnCOOH CHICOOH NaOOCHz CHIC OOH /N-CHr-CH2N HOOCH: CHzCOONa The tri-sodium salt of ethylene diamine tetra and the tetra-sodimn salt of ethylene diamine tetra acetic acid has the following structure:

NaOOCH: CHzCOONa The corresponding potassium and lithium salts of the di, tri and tetra sodium salts of ethylene diamine tetra acetic acid are prepared by substituting either lithium or potassium in place of the sodium in the foregoing di, tri and tetra sodium salts set forth above.

In addition to the use of the tetra alkali metal salt of ethylene diamine tetra acetic acid in my composition I may also use other salts of substituted acids of ethylene diamine in which the acetic acid radical is replaced by the higher organic acid radicals such as the higher saturated and unsaturated carboxy acids including propionic acid and butyric acid.

As a further modification of my invention I may produce an impression material by mixing calcium sulfate with a filler, a gel forming agent, such as an alkali metal salt of alginic, pectic or carboxymethyl cellulose, an alkali metal salt of ethylene diamine tetra acetic acid and water in sulficient amount to produce a plastic mass. In this composition the calcium sulfate reacts with the alkali metal salts of pectic, alginic and carboxymethyl cellulose acids to form a water insoluble gel. When calcium sulfate is used in my composition as the source of the alkaline earth metal sulfate I prefer to use it in the form of CaSO4. HzO. The alkali metal salt of the ethylene diamine tetra acetic acid controls the setting time of the composition.

As a further modification I may also use calcium in the form of the oxide or the hydroxide (slaked lime) as will be shown in the succeeding examples.

CHzC O ONa 4 The following are examples of my new composition:

Example I The following master batch, or mix, was tumbled in a cone blender:

110 grams diatomaceous earth 24 grams potassium alginate (low viscosity) 10 grams potassium alginate (high viscosity) grams lead monosilicate (an orthosilicate) 3.5 grams of tetrasodium salt of ethylene diamine tetra acetic acid (A) 11.5 grams of the above master batch were blended with 0.1 gram sodium fiuosilicate, 0.5 gram calcium sulfate (CaSOiJ/ HZO). To this blend there was added 25 cubic centimeters of water and the mixture was then thoroughly mixed with a spatula. This composition congealed in 1 minute and set in 3 minutes.

(B) 11.5 grams of the above master mix were blended with 0.750 gram of sodium fiuosilicate. To this blend there was added 25 cubic centimeters of water at 70 F. and this mixture was thoroughly spatulated (mixed). This final composition congealed in 2 minutes and set in 4 minutes.

(C) 11.5 grams of the above master mix were blended with 1.25 grams of aluminum fiuosilicate. To this blend there was added 25 cubic centimeters of water at 70 F. and this mixture was thoroughly spatulated (mixed). This final composition congealed in 6 minutes and produced a good set in 10 minutes.

(D) 11.5 grams of the above master mix were blended with 2.0 grams of aluminum fiuosilicate. To this blend 25 cubic centimeters of water at 70 F. were added and this mixture was thoroughly spatulated (mixed). This final composition congealed in 1% minutes and produced a good set in 4 minutes.

(E) 11.5 grams of the above master mix were blended with 0.5 gram of sodium fiuosilicate (NazSiFs) and 0.1 gram calcium sulfate (CaSO42H2O) Example II The following master mix was tumbled in a cone blender:

grams diatomaceous earth 24 grams sodium alginate (low viscosity) 10 grams sodium alginate (high viscosity) 85 grams lead monosilicate (an orthosilicate) 3.5 grams of the tetra sodium salt of ethylene diamine tetra acetic acid The low viscosity sodium alginate used in this master batch has a viscosity of 400 centipoises for a 1.0% aqueous solution when obtained at a temperature of 17 degrees centigrade. The high viscosity sodium alginate in this master batch has a viscosity of 1500 centipoises for a 1.0% aqueous solution when obtained at a temperature of 17 centigrade.

(A) 11.5 grams of the above master mix (Example II) were blended with 0.100 gram of sodium fiuosilicate. To this blend there was added 25 cubic centimeters of water at 70 F. and this mixture was then thoroughly spatulated (mixed). This composition congealed in l minutes at 78 F. and set in 4 minutes.

;-.,2;-65.,Z ,971 e e6 (B) 11.5 gramshfrtheiaboye master mix (Ex- =..-.this.hlendz25:;eubicrcentimeters ot-@wate1=.at.70 F. ample II). were blended with .050 gram of sodium -swere=added Elaimcompositiomset iIL-.-the bow1 .fiuo'silicate and 0.1'00 ,gram. jof calcium sulfate -while mixing.

(CaSO-ilZI-EO). "Tothis blend there was added -;(B)14.0 gramsz-nfstheiabovemastersmim-(Ex- --25 cubic centimeters .ofwater at 70? F. andthis 5 ample IV) were blended with 0.700 gram of the mixture was then thoroughly spatulat'ed (mixed). tetra sodium salt zoffethyleneiiiiamine tetra acetic This composition congealed in 5 minutes at 72"F. and. 0.100 gram .of. sodium fluosilicate. To and set in 12 minutes. "this'blend 25 cubic centimeters :of water at 70 F. (C) 11.5; gramsofrthe aboveamasterimix Exwere added and this mixture was" thoroughly ampleuII) wereieblended withx:0.200,;gram 1.101 710 spatulated (mixed).'1 lhiswcompositiomcongealed aluminum fluosilicate. Toisthis .-:blend=25wcubic n seconds.

centimeters of water. at '70? FLi'WeI'e added. IThis 'above masterimix {Exmi t r a th'oroughlyy spatulated am'ple- IV)--were: blendedtwith 0;350rgram'bfi;the This composition congealed in 3 mi ut t 72 tetra sodium salt of ethylene diamineJtetra-acetic and-set in G'minute 15 acid. 'To this blend 25cubic centimetersiof water -(D)" 11.5 grams-of the above-'master-mix (E);- .at 70?. F..were addedand this mixture was.thor- "ample I-I)"were blended with 0.100 grambf p'otasot h xspatillated (mixed) This'compO t On set sium fluosilicate. To this blend 25*cubic centifi l meters of water at 70 F. were added-"and" this ple mixture was thoroughE-y *spatulateddmixed) .120 The followin master mix ombatch, was-tum- This compositiom-congealed*-in' 1% m-inutesat bled in a Cone blendeumixmg mm) 72F. ands'et in 4 minutes.

(E) 1L5 'gramsof"theforegoing master-"mix mq t t "(Exam le II) were*blemietiwith i750' gramiof F gramme qe s i "calcium sulfate "tcasoiznzor and".500 :gram"of-.:;25 grams carbqxymethyl cellulose'medium'vis additional tetra sodium salt of ethylene diamine 905m) "tetra acetic acid." To this-'blend'there was added (A) 18.0 grams;..of zthe' ioregoingi mastenmix cubid'centimeters or waterat-70 F. This (Example V) were blended with 0.250 gram of composition congealed'in'l flyn'rinutes and'set in the disodium saltof ethylene'diamine-tetraiacetic 3'minutes. .430 acid, 0.250 gram of potassium fluosilicate and Example III 0.250; 'gram-- 'of calcium=-suifate (CaSO'AI-I'zO) "To this blend 25- cubic centimetersof water at :inzgc r i ifim r f orbatchiwasttumbled 70 F. were added and this-mixture" was then "thoroughly-spatuIated (mixed) lfhiscomposii IIO'g-rams diatomaceous earth tion 'congealed'in 2 minutes-and'set-in 5min'utes. 2e'grams potassiumalginatd-(HUOviscosity) --*10grams potassium a ginate" (high viscosity) irEmmile *85" grams lead monosilicate (lead orthosilicate) The following master mix or batchwastmnbled (A) 11.5 grams of the..ioregoing..master..mix in acone blender: .(Example lliDawereblended.with..0.350 gram of 100 grams diatomaceous earth the. disodiumsalt of-ethylenediaminetetra acetic 24 grams potassium a-Igi-nate (1100 viscosity) acid and 0.750 gram sodium fluosilicate. To this 1:10. g ya ms pqtassium .alginate :(high viscosity) blend 25 cubic centimeterspiwa-ter.at.70.8 Fwwere 85 f.g1}a,m -1ead,monosilioate addedwandrthis. mixture. was thoroughly spatu- Mlated. (mixed). This..comp0siti0n -congealed..in (A) 11.5 grams of the-abovemastermix .(Ex-

1%.minutesat-74f. F..and..set.in iminutes. ample VI) were blended with 1.0 gram sodium I (B)'.l1.5gramsofitheabove masteramixdExfluosilicate and 05350;:g1 am-of'an equal-mixture .ampleLII-I). .wereilolended. with. 0.350 gram .of tthe 0f -the "tetra; -potassium-salt of' -ethylene -diamine .trisddium. salt 4 of ethylene .diaminewtetra.:acetic tetra aeetic acid *a-nd diatomaceous earth. "To ,..acid andi.0..'7.50 .gram. of sodium. fluo'silicate. ..To this blend 25*c'ubic'centimeters bfwater at 70"F'. L'this blend 25 cubic centimeters of waterat-JOSF. were added and this mixturewas thoroughly were. addedand. .this. mixture. was'..thoroii h1y Spatulated- This" m n e al d in-1% spatulasted -(mixed). .This composition ..conminutesLandsatin 3 minutes.

ge'aled in 3%; minutes and set in 5 minutes. .IiBlfllLE,gramsbfithejabovemaster mixJXEx- (0).. 11.5..graznsof. the ..foregoing mastenimix .;am'pldVI). werehlendedwith 0.600 gram ;of..s0 .(EXarn IeJm). were Lblended. with!.0;700..gram .oI dium flu s i a ll-lflfls ra f .cal iumisiilfat "thetrisodiumsalt bfethylenediamine .tetraacetic (CaSO4 /2I-IzO) and 0.350 gram of an equal mixacid, 0.100,.gram.ofsodium fluos'ilicate and. 0.500 ture of the potassiumsaltrof ethylene diamine '..gram...iof,ca1cium sulfate (CaSOLy 'HZO). To tetra acetic. acid .and diatomaceous earth. To this blendf25 cubiccehtimeterspf. waterfatVOi F. thisblendthere'was' added 25"cubic centimeters were .added .andl this-mixture was..l-thoroughly of. water at F'."and=this mixtureywasjthoroughspatulated (mixed) ."Thiscomposition congealed "'lrspatul'ated' 1(rnixe'd). This final composition in 1% minutes and set in 7 minutes. set in 5 minutes.

Example Iv 2305 Example: VII Th following master batch-,- 'or mix was" tum- The -following.materials;werefimixedntogether bled in acone blender: i-.iand-.thoro ughly blended:

.100grams.diatomaceousearth 5.50 grams diatomaceous earth -grams.pectophi1L,.M...(sod1um. pe :270 1.20 gramselow. i-scosity..potassium,ialginate l00 .grams leadmonosilicate (an orthosilicate) 050 gram-high Viscosity potassium alginate 3,."(A)i lliig'lfamsfiofsthe.Zabovexzmasfier: '(E flz35osagranrtetra-isddiumisaltzofzethyleneidiamine sample. IV) were: blended with 0.350 gram: "Of the tetraracetieacid ttetrasodiumzsaltzof ethylene diamine' tetra acetic m sodiumf fluosilicate acid and 0.250 gnami of 'sodium fiuosilicate.T6975 9-600 am calcium sulfate (CaSOM/gI-I'zO) To the above 25 cubic centimeters of water at 70 F. were added and this mixture was thoroughly spatulated (mixed). This final composition congealed in 2% minutes and set in 5 minutes.

Example VIII The following materials were mixed together and thoroughly blended:

5.5 grams diatomaceous earth 1.2 grams low viscosity potassium alginate 0.5 gram high viscosity potassium alginate 0.350 gram tetra sodium salt of ethylene diamine tetra acetic acid 0.600 gram calcium sulfate (CaSOa2l-I2O) To the above blend 25 cubic centimeters of water at 70 F. were added and the mixture was thoroughly spatulated (mixed). This final composition congealed in 4 minutes at 74 F. and set in 8 minutes.

Example IX This example is a further modification of my composition in which slaked lime (Ca(OH)2) has been used as a source of calcium.

The following amounts of material oughly blended or mixed together:

were thor- To the above 25 cubic centimeters of water were added at 70 F. After spatulation with the water present this composition congealed in 1 minutes and set in 10 minutes.

Example X The following is an example wherein basic lead sulfate has been employed in my composition.

The following amounts of materials were thoroughly mixed or blended: 5.5 grams diatomaceous earth 1.2 grams potassium alginate (low viscosity) 0.5 gram potassium alginate (high viscosity) 0.35 gram tetra sodium salt of ethylene diamine tetra acetic acid 1.0 gram tribasic lead sulfate To the above blend 25 cubic centimeters of water were added at 70 F. and thoroughly mixed with the blend. This composition congealed in A; minute and set in 5 minutes.

Example XI This is another example in which basic lead sulfate is used in my composition.

The following amounts of materials were thoroughly blended and mixed together:

5.5 grams diatomaceous earth 1.2 grams sodium alginate (low viscosity) 0.5 gram sodium alginate (high viscosity) 0.5 gram tetra sodium salt of ethylene diamine tetra acetic acid 0.5 gram sodium fluosilicate 5.0 grams basic lead sulfate (Eagle Picher) This blend was spatulated with 25 cubic centimeters of water at 70 F. After spatulation this composition congealed in 1% minutes and set in 5 minutes.

Example XII This example is another modification of my composition in which lead oxide has been employed.

The following materials were thoroughly mixed 'or blended:

5.5 grams diatomaceous earth 2.2 grams sodium alginate (low viscosity) 0.350 gram tetra sodium salt of ethylene diamine tetra acetic acid 0.500 gram sodium fluosilicate 5.0 grams lead oxide This composition was thoroughly mixed with 25 cubic centimeters of water at F. This composition congealed in 1% minutes and set in 4 minutes.

I claim:

1. Impression taking material comprising a gel forming agent having an acid radical selected from the group consisting of alginic, pectic and carboxymethyl cellulose acids, an inorganic salt of the class consisting of calcium and lead salts having a metallic ion reactive with said acid radical of the gel forming agent to produce a water insoluble gel, and an alkali metal salt of a tetra carboxy acid of ethylene diamine as a retarder for such reaction.

2. A material as defined in claim 1, in which said inorganic salt is calcium sulfate.

3. A material as defined in claim 1, in which said inorganic salt is lead orthosilicate.

4. A material as defined in claim 1, in which said gel forming agent is an alkali metal alginate.

5. A material as defined in claim 1, in which said gel forming agent is an alkali metal pectate.

6. A material as defined in claim 1, in which said gel forming agent is an alkali metal salt of carboxymethyl cellulose.

7. A material as defined in claim 1, containing also a fiuosilicate of the class consisting of sodium fluosilicate, potassium fluosilicate, and aluminun fluosilicate.

8. Impression taking material comprising a gel forming agent having an acid radical selected from the group consisting af alginic, pectic and carboxymethyl cellulose acids, an inorganic salt of the class consisting of calcium and lead salts having a metallic ion reactive with said acid radica1 of the gel forming agent to produce a water insoluble gel, and an alkali metal salt of the group consisting of di, tri and tetra. potassium and sodium salts of ethylene diamine tetra acetic acid.

9. A material as defined in claim 8, in which said inorganic salt is reactive with the gel forming agent to produce the calcium salt thereof.

10. A material as defined in claim 8, in which said inorganic salt is reactive with the gel forming agent to produce the lead salt thereof.

11. A material as defined in claim 8, in which said gel forming agent is an alginate.

12. A material as defined in claim 8, containing also a fiuosilicate of the class consisting of alkali metal and aluminum fiuosilicates.

13. A material as defined in claim 8, in which said inorganic salt is CaSO4- /H2O.

14. An elastic gel composition comprising the reaction product of a metal ion of the class consisting of lead and calcium, with an acid radical of the group consisting of alginic, pectic and carboxymethyl cellulose acids, and an alkali metal salt of a tetra carboxy acid of ethylene diamine uniformly distributed within the gel.

15. An elastic gel composition comprising the reaction product of a, metal ion of the class consisting of lead and calcium, with an acid radical of the group consisting of alginic, pectic and carboxymethyl cellulose acids, and a compound of the group consisting of di, tri, and tetra potassium and sodium salts of ethylene diamine tetra acetic acid.

EDWIN H. LOCHRIDGE.

Number Name Date Munz May 6, 1941 15 Number Number Name Date Freeman et a1. Jan. 19, 1943 Freeman et al Oct. 12, 1943 Vallandigham Dec. 4, 1945 Noyes June 17, 1947 Auer Jan. 6, 1948 Reid Jan. 31, 1950 Parr Mar. 7, 1950 FOREIGN PATENTS Country Date Great Britain Jan. 27, 1930 

1. IMPRESSION TAKING MATERIAL COMPRISING A GEL FORMING AGENT HAVING AN ACID RADICAL SELECTED FROM THE GROUP CONSISTING OF ALGINIC, PECTIC AND CARBOXYMETHYL CELLULOSE ACIDS, AN INORGANIC SALT OF THE CLASS CONSISTING OF CALCIUM AND LEAD SALTS HAVING A METALLIC ION REACTIVE WITH SAID ACID RADICAL OF THE GEL FORMING AGENT OT PRODUCE A WATER INSOLUBLE GEL, AND AN ALKALI METAL SALT OF A TETRA CARBOXY ACID OF ETHYLENE DIAMINE AS A RETARDER FOR SUCH REACTION. 